A typical gas turbine burner assembly, as it is mainly used in so called canannular combustion systems is, for example, described in U.S. Pat. No. 6,082,111 and in US 2004/0055306 A1. Such burner assemblies typically comprise a cover plate to which a support housing is mounted. The support housing comprises a manifold with fuel and oil passages machined inside and fuel nozzles, so called rockets, extending from the manifold and being supplied with fuel through the gas and oil passages. Injection holes in the fuel nozzles guide the fuel out of the nozzles into a flow path of air delivered by the compressor of the gas turbine to the burner assembly. Swirlers are present in this flow path for providing a swirl to achieve a thorough mixing of fuel and air. This design of the support housing includes eight fuel nozzles (rockets), for example, which are welded to the manifold and also to the swirlers of a main swirler assembly.
However, the design described in the mentioned prior art is compromised by high costs for production of the manifold since machining of gas and oil channels into the manifold is elaborate and requires a high thickness of the manifold. After machining the fuel passages, cover plates are welded onto the manifold in order to close the passages. During the welding process care has to be taken not to induce too much stress in the manifold material due to the heat introduced during the welding process. Moreover, the material used for the manifold needs to be produced from a corrosion-resistant material since the fuel comes into contact with the walls of the gas or oil channels machined into the manifold. In addition, in use of the burner assembly the manifold will have a considerably higher temperature than the fuel delivered through the manifold. Hence, the material also needs to be stress resistant. Therefore, the manifold and the fuel nozzles of the state of the art burner assemblies are usually made from forged pieces which need to be finished by abrasive techniques in order to reduce susceptibility to tension cracks. The material requirements increase the cost for producing the manifold. In addition, corrosion resistant and stress resistant materials are usually difficult to machine, which even more increases production costs.